@dan They are built in to the batteries, the ones that shut them off if they get below a certain voltage? (these drop off at about 2.5 V.) cool thing is if lithiums don't work out, i already have a 6x AAA setup that plugs into a 9V slot, and i can setup a 6x AAA one just as easily. it also runs off of a single 9V, but I'm guessing not much more than an hour or two on dim... those things can't hold too much. @ahicks As far as a fuse, I'm only drawing 1A out of it, do i really need one?

Yes you still need a fuse! It's in case you accidently short the things. Otherwise they have a nasty habit of going BANG and then catching on fire!

As for the Low Voltage Cutoff (LVC) circuit that Dan mentions, the 2.5V in your batteries is a bit low and might shorten the life of the cells. However, luckily it looks from your description that the light might cut off by itself before that which is great! Just watch though that you don't leave it on once it's cut out just in case the buckpuck still tries to suck some small current out which drains the cells.

Standard cell phone batts won't work, or for long, they can't handle the current draw. Look into some R/C batteries. Some nice, small Li cells w/ built in protection circuits can be found. Price depends on how much capacity you want. j